Department of Primatology

Bonobos: behavioral physiology, socio-ecology, and sociality

(directed by Gottfried Hohmann & Barbara Fruth)

Bonobos are separated from other species of African Great Apes by the river Congo and evidence suggests that the speciation of Pan is the result of the geographic separation. More so than other apes, their social system is characterized by social tolerance, nepotism, and female cooperation. Our central aim is to understand the selective forces that have shaped the evolution of their social system. Such information is crucial for assessing how hominoids differ from other primates, and what separates them from humans.

The majority of information from wild bonobos is obtained by systematic behavioral observations of focal individuals. In most cases, observations are combined with physiological and molecular data to explore causes and consequences of social behavior. Using material such as urine, feces, and hair that can be collected non-invasively from wild apes, we are able to identify kin relationships and measure hormones, stable isotopes and other physiological markers. The work on wild bonobos is complemented by studies on captive bonobos. This approach takes advantage of having control of social and environmental parameters and permits validation of physiological markers and assessment of topics such as digestive kinetics, digestive efficiency, and hormonal responses to social and environmental stimuli.